new version....

[ctech]

Hello all

We have a new version (EPM 1.2). The main change was to go from an IGBT switch to thyristors and using thicker copper wire in the winding...

The IGBT has the problem that when one switches it off under a high current condition it dies.  This can happen when there is too much noise on the signal or power line. The switch to thyristors prevents this from happening. It still won't work right with excessive noise but nothing will break.

Another advantage of the change to thyristors is that the Vcc range is now from 2.7-7.5V so there 

is no need for a separate 5V power rail. The thicker winding with thicker insulation improves the  robustness of the EPM.

The units already shipped are version EPM 1.0 and EPM 1.02. We will be shipping EPM 1.2 from now on. There will be more improved versions one of which is in the manufacturing prototype phase right now.

regards

Andreas

[hirez]

Thanks for the update!

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[M Donahoo]

Thanks for the update Andreas!

Looking forward to using the open grab with my R10 quadrotor.

 

M

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[Jasper -]

Hi Andreas,

I've received a mail that my kit was sent out two weeks ago, so I'll assume I get the 1.0x version. I have not received it yet, but customs are always slow here in Germany.

Can this 1.0x board be upgraded to the thyristors? It sounds like a big improvement if it can prevent damage. Or is the board layout different? If its possible what parts would I need to order?

Best regards,

Jasper

[ctech]

sorry its difficult to change to that, for one thing the gate and cathode are switch and i had to add a delay circuit to prevent charging for the first ~1ms because the charging current is above the holding current and the thyristors never turn off....

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